661611755 has 8 divisors (see below), whose sum is σ = 907353312. Its totient is φ = 453676608.

The previous prime is 661611739. The next prime is 661611761. The reversal of 661611755 is 557116166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661611755 - 2⁴ = 661611739 is a prime.

It is a super-2 number, since 2×661611755² = 875460228708360050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9451562 + ... + 9451631.

It is an arithmetic number, because the mean of its divisors is an integer number (113419164).

Almost surely, 2^661611755 is an apocalyptic number.

661611755 is a deficient number, since it is larger than the sum of its proper divisors (245741557).

661611755 is a wasteful number, since it uses less digits than its factorization.

661611755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18903205.

The product of its digits is 37800, while the sum is 38.

The square root of 661611755 is about 25721.8147687911. The cubic root of 661611755 is about 871.3669246072.

The spelling of 661611755 in words is "six hundred sixty-one million, six hundred eleven thousand, seven hundred fifty-five".